Spherically Convergent Shear Waves during Blunt Head Trauma

Martin Ostoja-Starzewski

We report on transient stress waves occurring during blunt head trauma. The basis of the study is an MRI-based computational model, which was previously validated by tagged MRI and harmonic phase (HARP) imaging analysis techniques on in vivo human brain deformation data. It has been confirmed through side and top impact simulations that, just like in earlier studies focused on frontal impact, the pressure input to the head gives rise not only to a fast pressure wave in the brain, but also to a slow, and potentially much more damaging, shear wave that converges spherically towards the brain center. The wave amplification due to spherical geometry is balanced by wave damping due to viscoelastic brain tissues and the distortion of wavefronts by a heterogeneous brain structure.

Martin Ostoja-Starzewski is a professor in the Department of Mechanical Science and Engineering, the Institute for Condensed Matter Theory, and the Beckman Institute for Advanced Science and Technology at the University of Illinois at Urbana-Champaign. He did his undergraduate studies at the Cracow University of Technology, Poland, and went on to earn his Master’s and Ph.D. degrees in mechanical engineering at McGill University, Canada. His research is in (thermo)mechanics of random/multiscale media, helices, continuum theories, and biophysical applications. He (co)authored 160+ journal papers and two books: Microstructural Randomness and Scaling in Mechanics of Materials, CRC Press (2008), and Thermoelasticity with Finite Wave Speeds, Oxford University Press (2010). He (co-)edited 13 books/journal special issues and (co-)organized numerous meetings. He was Assoc. Editor of ASME J. Applied Mechanics (2006−2012), and currently is on the editorial boards of J. Thermal Stresses, Probabilistic Engineering Mechanics, Actual Problems Aviation Aerospace Systems, Int. J. Damage Mechanics, Archive of Applied Mechanics, Acta Mechanica, Int. J. Aeronaut. Space Sciences, and J. Applied Mathematics (Hindawi). He is also co-Editor of the CRC Modern Mechanics and Mathematics Series, and Chair Managing Editor of Mathematics and Mechanics of Complex Systems journal. He is a Fellow of ASME, AAM, and WIF, and an Assoc. Fellow of AIAA. In the winter of 2012, he was Timoshenko Distinguished Visitor at Stanford University.